Process of separating solids of different specific gravities.



"UNITED STATES PATENT OFFICE.

ADBIAAN NAG-ELVOOBT, OF NEW YORK, N. Y., ASSIGNOB, BY MESNE ASSIGNMENTS, 'I'O VIRGINIA HALOID COMPANY, OF WILMINGTON, DELAWARE.

PROGESS OF SEPARATDTG SOLIDS OI DIFFERENT SPECIFIC GBAVI'IIES.

No Drawing.

- which the following is a full, clear, and exact description.

In the gravity separation of solids by means of a liquid, a certain amount of the liquid is carried ofi' with the separated constituents. The separating liquid is usually too valuable to be lost and aneconomical execution of the process necessitates the recovery of the liquid ascarried off by the solids so that it may be returned to the separating tank for re-use.

In an application filed by me on the 16th of June, 1916, Serial No. 103,937, I have described a process which I have applied to the separation of pure iron ore from silicious gangu'eg in which I employ, as a liquid separant, tin bromid or arsemous bromid, or a mixture of the two, or some other suitable separant, and subject the separated solids, after their emergence from the separating tank, toa washing action in liquid carbon bisulfid or some other recovery llquid which is a solvent of the bromid or other separant and .which has a boiling point substantially below that of the separant, the washing aetion being carried on at a temperature below that of the b0 f 'point of the recovery liquid. The solut1on of the separantand the recovery liquid that has been used to wash off the sohds is then subjected to heat to evaporate oil the recovery liquid, while the solids, coated with the recovery liquid, are also subjected to heat to drive oil the recovery liquid; the recovery liquid heing. condensed and re-used in the recovery step 1 of the process, while the separant is re-used 1n the separating step of. the .process. In thefabove named application I claim the recovery, from the separated solids, of the liquid bromid, or other separant'having a specific gravity between the specific gravities of the solids, by washing the solids in liquid carbon bisulfid, or other solvent of the sepairant having a boiling point below that of the separant, at a temperature above 'the melting point of the separant and below the Specification of Letters Patent.

Application filed September 1, 1916. Serial No. 118,013.

vent; but instead of using,

Patented Oct. 30,1917.

boiling point of the solvent, and then recovering the separant from the solution by evaporating the solvent.

My present invention is, in one aspect, an improvement upon, and an outgrowth of, theprocess just described, while in another aspect, it is an independent invention, in that it is applicable to a wider range of liquids than that to which the described process is applicable.

While the bromids above mentioned, by reason of their specific gravities and other qualities, have characteristics closely approximating the ideal requirements of a separating liquid, it is well known that different kinds of ore have different specific gravities, and, therefore, even if, as applied to one kind of ore, the separating liquid has an intermediate specific gravity corresponding closely to what is theoretically required, it may be unavailable, or undesirable, for another kind of ore. It should also be borne in mind that the ideal product which is most suitable for smelting should be composed not of pure iron ore, but of iron ore having a fairly defined proportion of silicious material. With each ore of known characteristics, it is ossible to calculate the theoretically required separant, and it is one of the objects of my invention to provide a process .whereby a separant of the specific gravity required for any ore may be provided; while at the same time provision is made for the recovery of 'the separant from the solids so that it may uent of the separating liquid and to employ liquid carbon bisulfid as the recovery s01- as a separant, the bromid in its pure state, I use it solution with such a quantity of the carbon bisulfid (which has a substantially lower specific gravity) as will give a separant of. the desired speclfic gravlty. The separated solids are then sub ected, as heretofore, to the washing action of pure'carbon bisulfid in order to remove therefrom the adherent specific gravity of-the separant, and the washed solids are subjected to the mild heat required to evaporate'ofi' the carbon bisulfid, which is condensed and re-used. The solution from the recovery vesof tin bromid in carbon bisulfid, the re-' .are separated in this solution,

sel, however, is preferably not heated to the bon bisulfid, is driven ofi than that mentioned, suflicient carbon bisulfid is afterward added to provide a separant of the desired specific gravity. I, therefore, desire.

it to be understood that my process contemplates either driving oil the exact quantity of carbon bisulfid required to leave a solution having the proportions of heavy salt and carbon bisulfid desired for the separant, or driving off the carbon bisulfid in such quantity as to leave a solution containing less carbon bisulfid than is required to proytide a separant of the desired specific'grav- 1 y.

It will be understood that the practice of this process leaves open a fairly wide range of substances from which to select the solvent recovery liquid andthe main constituent of the separant. The latter should be a comparatively heavy salt, while the recovery liquid should be one which does not chemically react or combine with the heavier salt except to form the solution. I

Thus, assume that the required specific gravity of the separant is 3.10. We can make such a separant by using a solution quired percentage of the two constituents being readily calculable. After the solids they are then separately subjected to the washing action of pure carbon bisulfid, whereby the separant is removed from the solids. The resultant solution of carbon bisulfid and bromid is of a specific gravity but little greater than that of carbon bisulfid itself, because it is mostly carbon bisulfid with a relatively very small quantity of tin bromid in solution. From this solution, the major portion of the carbon bisulfid is evaporated until the residual liquid inthe evaporator contains the same proportion of bromid and carbon bisulfid as the or' al separant.

Having now y described my mvention, what I claim and desire to protect by Let ters Patent is:

1. In the separation of solids of difierent specific gravitles, the process which consists in se ting the solids in a solution of two liquids of difierent specific gravities but each of a specific gravity greater than that of water, washing the separated solids that are thus wet with the separant in a separate uantig of the lighter liquid to eliminate 2mm e solids the heavier constituent of the separant, and then separating from the solution at least all the solvent in excess of that required to leave a solution having the desired specific gravity of the separant.

2. In the separation of solids of difierent specific gravities, the process which consists in separating the solids-in a solution of two liquids of different specific gravities the lighter of which is of a specific gravity greater than that of water and has a substantially lower boiling point than the heavier, eliminating from the separated solids, thus wet with the separant, the heavier constituent of the separant by washing with a separate quantity of the lighter liquid, and distilling off from the solution at least so much of the lighter liquid as will leave a solution of the two liquids in leave a liquid having the characteristics of the original separant.

4. In the separation of solids of difierent specific gravities, the process which consists in separating the solids in a liquid separant composed of a solution of a salt in a solvent thereof of a specific gravity greater than that of water but of lower specific gravity, and having a substantially lower boiling point, than the salt, washing the solids that are thus wet with the separant in a separate uantity of the solvent, and then sub ecting t e solution of washing liquid and separant to heat to the extent required to drlve of at least all the solvent in excess of that required to leave a separating solution of the desired specific gravity.

5. In the separation of solids of different specific gravities, the process which consists in separating the solids in a solution of a relativel heavy salt in carbon bisulfid, eliminating cm the solids the heavy solution by washing with carbon bisulfid, and distilling off from the resultant solution at least the excess of carbon bisulfid required to provide a separant of the desired specific gravity.

6. In specific gravities, the rocess which consists in separating the sohds in a solution of a bromid in carbon bisulfid, recovering the bromid from the solids that are thus wet with the separant by washin the latter with carbon bisulfid and distilhng of! from the separation of solids of different i the solution an amount of carbon bisulfid at least equal to that used for washing.

7. In the separation of solids of difierent specific gravities, the process which consists in separating the sohds in one liquid and then washing them in another liquid,- both liquids having a specific gravity above that of water, the separating liquid comprising a solution of a relatively heavy salt in the washing liquid.

8. In the separation of solids of difierent specific gravities, the process which consists in separating the solids in one liquid and then washing them in another liquid, the separating liquid comprising a solution of a relatively heavy salt in the washing liquid and evaporating and condensing the washing liquid and reusing in the washing operation the liquid so evaporated and condensed.

9. In the separation of solids of different specific gravitiesy the process which consists in separating the solids in a solution of two liquids of diiferent specific gravities, washing the separated solids that are thus wet with the separant in a separate quantity of the lighter liquid to eliminate from the solids the heavier constituent of the separant, then separating from the solution at least all the solvent in excess of that required to leave a solution having the desired specific gravity of the separant and reusing in the washing operation the solvent so separated.

10. In the separation of solids of diflerent specific gravities, the process which consists in separating the solids in a solution of a bromid and carbon bisulfid.

11. In the separation of solids of diflferent specific gravities, the process which consists in separating the solids in a solution of a bromid and carbon bisulfid and then washing the solids in carbon bisulfid.

12. In the separation of solids of different specific gravities, the process which consists in separating the solids in a solution of a relatively heavy salt and carbon bisulfid.

13. In the separation of solids of different specific gravities,' the process which consists in separating the solids in a solution of a relatively heavy salt and carbon bisulfid and then washing the solids in carbon bisulfid.

In testimony of which invention, I have hereunto set my hand, at New York, N. Y., on this 30 day of August, 1916.

'ADRIAAN NAGELVOORT. 

